1. Field of the Invention
The present invention relates to the isomerization and/or rearrangement of polychlorobenzenes, and, more especially, to the preparation of polychlorobenzenes by rearrangement and/or isomerization of certain polychlorobenzenes congeneric thereto.
2. Description of the Prior Art
The isomerization/rearrangement of the polybromobenzenes is known to this art. Thus, J. F. Bunnett and Charles E. Moyer, Jr., Journal of the American Chemical Society, 93:5, pages 1183-1205 (Mar. 10, 1971), feature the reaction of sodium amide in liquid ammonia with 1,2,4-tribromobenzene. The latter compound rearranges into 1,3,5-tribromobenzene. A small amount of the di- and tetrabromo derivatives is also obtained. Similarly, the publication describes obtaining, from 1-iodo-2,4-dibromobenzene, a mixture containing the 1,3,5-isomer, together with 1,2,4-tribromobenzene, 1,3,5-tribromobenzene and 1-bromo-3,5-diiodobenzene. The article further describes the reaction of NaNH.sub.2 in liquid ammonia with 1-bromo-2,4-dichlorobenzene, 1-iodo-4-bromochlorobenzene and 1-iodo-2,4,6-tribromobenzene.
The authors too have attempted to react, under the same conditions, the polychlorobenzenes (especially 1,2,4-trichlorobenzene). But this attempt was unsuccessful (page 1185, right-hand column).